The subject invention relates to a semiconductor light emitting device, more specifically relates to the packaging of semiconductor light emitting device and other applications. Semiconductor light emitting devices, such as Light Emitting Diodes (LED) or laser diodes, are widely used to many applications. As known to the persons skilled in the art, a semiconductor light emitting device comprises one or more semiconductor layer disposed to emit coherent and/or incoherent light after conducting to electricity. It is also known that a semiconductor light emitting device is packaged to provide external electrical connectivity, heat dissipation, lens or wave guide, environmental protection and/or other functions.
For example, it may be desirable to change light from a semiconductor light emitting device from one direction to another. In some applications, it may be desirable to guide the light from the light emitting surface that is perpendicular (referred to as “vertical” light here) to the semiconductor light emitting device to a direction of the light emitting surface that is parallel (referred to as “horizontal” direction here) to the semiconductor light emitting device. It may also be desirable to re-direct the light within a range of 360° above the horizontal direction. This kind of direction changing can be used to backlight applications, such as backlights of Liquid Crystal Displays (LCDs) or “light emitting walls” applications.
West et al disclosed U.S. Pat. No. 6,679,621, entitled “Side Emitting LED And Lens”, wherein the abstract states: “The present invention discloses, comprising a bottom surface, a reflecting surface, a first refracting surface obliquely angled with respect to a central axis of the lens, and a second refracting surface extending as a smooth curve from the bottom surface to the first refracting surface. Light entering the lens through the bottom surface and directly incident on the reflecting surface is reflected from the reflecting surface to the first refracting surface and refracted by the first refracting surface to exit the lens in a direction substantially perpendicular to the central axis of the lens. Light entering the lens through the bottom surface and directly incident on the second refracting surface is refracted by the second refracting surface to exit the lens in a direction substantially perpendicular to the central axis of the lens. The lens may be advantageously employed with LEDs, for example, to provide side-emitting light-emitting devices. A lens cap attachable to a lens is also provided.”
Additionally, Negley et al also disclosed U.S. Patent Publication No. 2006/0018122, entitled “Reflective Optical Elements For Semiconductor Light Emitting Devices”, wherein the abstract states: “The present invention discloses a optical element for semiconductor light emitting devices, comprising a body that is configured to attach to a semiconductor light emitting device. The body includes an integral lens. A mirror is provided in and/or on the body. The body, the lens and the mirror are positioned such that, in operation, light that is emitted from the semiconductor light emitting device enters the body, is reflected from the mirror and passes through the lens to emerge from the body.”
The prior art described above cannot provide a high efficiency side emitting. In fact, when applying semiconductor light emitting devices on several backlight applications, the aim is to have semiconductor light emitting devices provide uniform light source and/or reduce the number of light emitting devices required and/or dynamically control multiblock region. Therefore, the present invention is able to achieve the above goals.